Cyclohexane compounds used in liquid crystalline mixtures

Abstract

Compounds of the formula ##STR1## wherein n stands for the number 0 or 1; R 1 denotes a group R 3 or R 3 --A 3 --Z 2 -- and R 2 denotes a group R 4 or R 4 --A 4 --Z 3 --; ring A 1 is unsubstituted or halogen-, cyano- and/or methylsubstituted 1,4-phenylene in which optionally 1 CH group or 2 CH groups is/are replaced by nitrogen; A 3 A 4 and ring A 2 each independently represent unsubstituted or halogen-, cyano- and/or methyl- -substituted 1,4-phenylene in which optionally 1 CH group or 2 CH groups is/are replaced by nitrogen or trans-1,4-cyclohexylene, trans-1,3-dioxane-2,5-diyl, 1-cyano-trans-1,4-cyclohexylene, bicyclo[2.2.2]octane- -1,4-diyl, naphthalene-2,6-diyl, tetralin-2,6-diyl or trans-decalin-2,6- diyl; Z 1 , Z 2 and Z 3 each independently are a single covalent bond, --COO--, --OOC--, --CH 2 O--, --OCH 2 --, --CH 2 CH 2 --, --C|C--, --(CH 2 ) 3 O--, --O(CH 2 ) 3 --, --(CH 2 ) 4 -- or the trans form of --CH═CH-- CH 2 O-- or --OCH 2 --CH═CH--; R 3 and R 4 each independently denote halogen, cyano, --NCS, --CF 3 , --OCF 3 or alkyl in which optionally one >CH--CH< is replaced by >C═C< and/or optionally one methylene group or two non- adjacent methylene groups is/are replaced by --O--, --COO-- and/or --OOC-- and/or optionally one methylene group is replaced by --CHX--; and X is halogen, cyano or methyl, as well as liquid crystalline mixtures which contain such compounds and their use for electro-optical purposes.

We claim: 
     
       1. A compound of formula ##STR9## wherein n is 0 or 1: R 1  represents a group R 3  or R 3  --A 3  --Z 2  --; R 2  is a group R 4  or R 4  --A 4  --Z 3  --; ring A 1  represents 1,4-phenylene or 1,4-phenylene having 1CH or 2CH groups replaced by nitrogen, the rings A 1  being unsubstituted or substituted with at least one of halogen, cyano or methyl: A 3 , A 4  and ring A 2  each independently represent 1,4-phenylene or 1,4-phenylene having 1CH or 2CH groups replaced by nitrogen, each of the 1,4-phenylene or 1,4-phenylene having 1CH or 2CH groups replaced by nitrogen being unsubstituted or substituted with at least one of halogen, cyano or methyl, or trans-1,4-cyclohexylene, trans-1,3-dioxane-2,5-diyl, 1-cyano-trans-1,4-cyclohexylene, bicyclo [2.2.2]octane-1,4-diyl, naphthalene-2,6-diyl, tetralin-2,6-diyl or and trans-decalin-2,6-diyl; Z 1 , Z 2  and Z 3  each independently represent a single covalent bond, --COO--, --OOC--, CH 2  O--, --OCH 2  --, --CH 2  CH 2  --, --C|C--, --(CH 2 ) 3 )--, --O(CH 2 ) 3  --, --(CH 2 ) 4  -- or a trans form of --CH═CH--CH 2  O-- or --OCH 2  --CH═CH--; R 3  and R 4  have a maximum of 18 carbon atoms and each independently represent halogen, cyano, --NCS, --CF 3 , --OCF 3 , alkyl, alkyl having one >CH--CH< replaced by >C═C<, alkyl having one methylene group or two non-adjacent methylene groups replaced by at least one of --O--, --COO-- or --OOC--, alkyl having one methylene group replaced by --CHX--, alkyl with one methylene group or two non-adjacent methylene groups being replaced by at least one of --O--, --COO-- or --OOC--, and one methylene group being replaced by --CHX--, alkyl having >CH--CH< replaced by >C═C< with one methylene group or two non-adjacent methylene groups being replaced by at least one of --O--, --COO-- or --OOC--, alkyl having one >CH--CH< replaced by >C═C< with one methylene group replaced by --CHX--, and alkyl having one >CH--CH< replaced by >C═C< with one methylene or two non-adjacent methylene groups being replaced by at least one of --O--, --COO-- or --OOC--, and one methylene group being replaced by --CHX--; and X represents halogen, cyano or methyl. 
     
     
       2. A compound according to claim 1 of formula ##STR10## wherein n, R 1  R 2 , Z 1  and ring A 2  have the significances given in claim 1 and X 1  and X 2  each independently denote hydrogen, halogen, cyano or methyl. 
     
     
       3. A compound according to claim 1, wherein A 3  and A 4  each independently represent trans-1,4-cyclohexylene or 1,4-phenylene, the 1,4-phenylene being unsubstituted or substituted with at least one of halogen, cyano or methyl. 
     
     
       4. A compound according to claim 1, wherein ring A 2  represents unsubstituted 1,4-phenylene, 1,4-phenylene which is monosubstituted or 2,3-disubstituted with at least one of halogen, cyano or methyl, or trans-1,4-cyclohexylene, trans-1,3-dioxane-2,5-diyl, 1-cyano-trans-1,4-cyclohexylene, bicyclo[2.2.2]octane-1,4-diyl, naphthalene-2,6-diyl, tetralin-2,6-diyl, trans-decalin-2,6-diyl, pyridine-2,5-diyl, pyrimidine-2,5-diyl or pyrazine-2,5-diyl. 
     
     
       5. A compound according to claim 1, wherein Z 1 , Z 2  and Z 3  each are a single covalent bond. 
     
     
       6. A compound according to claim 1, wherein two of the groups Z 1 , Z 2  and Z 3  each are a single covalent bond and one of the groups Z 1 , Z 2  and Z 3  is --COO--, --OOC--, --CH 2  O--, --OCH 2  --, --CH 2  CH 2  --, --C|C--, --(CH 2 ) 3  O--, --O(CH 2 ) 3  O--, --(CH 2 ) 4  -- or the trans form of --CH═CH--CH 2  O-- or --OCH 2  --CH═CH. 
     
     
       7. A compound according to claim 1 of formulas ##STR11## wherein R 3 , R 4  and Z 3  have the significances given in claim 1 X 1 , X 2 , X 3  and X 4  each independently denote hydrogen, halogen, cyano or methyl, Z 4  is a single covalent bond, --COO--, --OOC-- or --C|C--; Z 5  denotes a single covalent bond, --OOC--, --OCH 2  --, --CH 2  CH 2  --, --C|C--, --O(CH 2 )3--, --(CH 2 ) 4  -- or the trans form of --OCH 2  --CH═CH--; and ring A 5  represents pyridine-2,5-diyl, pyrimidine-2,5-diyl, pyrazine-2,5-diyl, trans-1,3-dioxane-2,5-diyl, bicyclo[2.2.2]octane-1,4-diyl, naphthalene-2,6-diyl, tetralin-2,6-diyl or trans-decalin-2,6-diyl. 
     
     
       8. A compound according to claim 2 wherein X 1 , X 2 , each independently are hydrogen or fluorine. 
     
     
       9. A compound according to claim 7 wherein X 1 , X 2 , X 3  and X 4  each independently are hydrogen or fluorine. 
     
     
       10. A compound according to claim 1 wherein R 3  and R 4  each independently denote alkyl, alkyl having one CH--CH< replaced by >C═C<, alkyl having one methylene group or two non-adjacent methylene groups replaced by at least one of --O--, --COO-- or --OOC-- , alkyl having one methylene group replaced by --CHX--, alkyl having one methylene group or two non-adjacent methylene groups replaced by at least one of --O--, --COO-- or --OOC-- and having one methylene group replaced by --CHX--, alkyl having one CH--CH< replaced by >C═C< with one methylene group or two non-adjacent methylene groups replaced by at least one of --O--, --COO-- or --OOC--, alkyl having one >CH--CH< replaced by >C═C< with one methylene group replaced by --CHX-- and alkyl having one >CH--CH< replaced by >C═C< with one methylene group or two non-adjacent methylene groups replaced by at least one of --O--, --COO-- or --OOC-- and having one methylene group replaced by --CHX--; or R 4  also can be halogen, cyano, --NCS, --CF 3  or --OCF 3 . 
     
     
       11. A compound according to claim 1, wherein R 3  and R 4  each have a maximum of 12 carbon atoms. 
     
     
       12. A compound according to claim 1, wherein R 3  is alkyl, alkenyl, alkoxy, alkenyloxy, alkoxycarbonyl, alkenyloxycarbonyl, alkanoyloxy or alkenoyloxy. 
     
     
       13. A compound according to claim 13, wherein R 3  is alkyl or alkenyl. 
     
     
       14. A compound according to claim 1, wherein R 4  is alkyl, alkenyl, alkoxy, alkenyloxy, alkoxycarbonyl, alkenyloxycarbonyl, alkanoyloxy, alkenoyloxy, halogen, cyano, --NCS, --CF 3  or --OCF 3 . 
     
     
       15. A liquid crystalline mixture with at least 2 components, wherein at least one component is a compound of formula ##STR12## wherein n is 0 or 1; R 1  represents a group R 3  or R 3  --A 3  --Z 2  --; R 2  is a group R 4  or R 4  --A 4  --Z 3  --; ring A 1  represents 1,4-phenylene, or 1,4-phenylene having 1CH or 2CH groups replaced by nitrogen, the rings A 1  being unsubstituted or substituted with at least one of halogen, cyano or methyl; A 3 , A 4  and ring A 2  each independently represent 1,4-phenylene or 1,4-phenylene having 1CH or 2CH groups replaced by nitrogen, each of the 1,4-phenylene or 1,4-phenylene having 1CH or 2CH groups replaced by nitrogen being unsubstituted or substituted with at least one of halogen, cyano or methyl, or trans-1,4-cyclohexylene, trans-1,3-dioxane-2,5-diyl, 1-cyano-trans-1,4-cyclohexylene, bicyclo [2.2.2]octane-1,4-diyl, naphthalene-2,6-diyl, tetralin-2,6-diyl or and trans-decalin-2,6-diyl; Z 1 , Z 2   and Z 3  each independently represent a single covalent bond, --COO--, --OOC--, CH 2  O--, --OCH 2  --, --CH 2  CH 2  --, --C|--, --(CH 2 ) 3  --, --O(CH 2 ) 3  --, --(CH 2 ) 4  -- or a trans form of --CH═CH--CH 2  O-- or --OCH 2  --CH═CH--; R 3  and R 4  have a maximum of 18 carbon atoms and each independently represent halogen, cyano, --NCS, --CF 3 , --OCF 3 , alkyl, alkyl having one >CH--CH< replaced by >C═C<, alkyl having one methylene group or two non-adjacent methylene groups replaced by at least one of --O--, --COO-- or --OOC--, alkyl having one methylene group replaced by --CHX--, alkyl with one methylene group or two non-adjacent methylene groups being replaced by at least one of --O--, --COO--, or --OOC--, and one methylene group being replaced by --CHX--, alkyl having >CH--CH< replaced by >C═C< with one methylene group or two non-adjacent methylene groups being replaced by at least one of --O--, --COO-- or --OOC--, alkyl having one >CH--CH< replaced by >C═C< with one methylene group replaced by --CHX--, and alkyl having one >CH--CH< replaced by >C═C< with one methylene or two non-adjacent methylene groups being replaced by at least one of --O--, --COO-- or --OOC--, and one methylene group being replaced by --CHX--; and X represents halogen, cyano or methyl. 
     
     
       16. A liquid crystal cell comprising: a) two plate means;   b) liquid crystal means disposed between the two plate means and including a compound of formula ##STR13##  wherein n is 0 or 1: R 1  represents a group R 3  or R 3  --A 3  --Z 3  --; R 2  is a group R 4  or R 4  --A 4  --Z 3  --; ring A 1  represents 1,4-phenylene, or 1,4-phenylene having 1CH or 2CH groups replaced by nitrogen, the rings A 1  being unsubstituted or substituted with at least one of halogen, cyano or methyl; A 3 , A 4  and ring A 2  each independently represent 1,4-phenylene or 1,4-phenylene having 1CH or 2CH groups replaced by nitrogen, each of the 1,4-phenylene or 1,4-phenylene having 1CH or 2CH groups replaced by nitrogen being unsubstituted or substituted with at least one of halogen, cyano or methyl, or trans-1,4-cyclohexylene, trans-1,3-dioxane-2,5-diyl, 1-cyano-trans-1,4-cyclohexylene, bicyclo [2.2.2]octane-1,4-diyl, naphthalene-2,6-diyl, tetralin-2,6-diyl or and trans-decalin-2,6-diyl; Z 1 , Z.sup. 2 and Z 3  each independently represent a single covalent bond, --COO--, --OOC--, CH 2  O--, --OCH 2  --, --CH 2  CH 2  --, --C|C--, --(CH 2 ) 3  --, --O(CH 2 ) 3  --, --(CH 2 ) 4  -- or a trans form of --CH═CH--CH 2  O-- or --OCH 2  --CH═CH--; R 3  and R 4  have a maximum of 18 carbon atoms each independently represent halogen, cyano, --NCS, --CF 3 , --OC 3 , alkyl, alkyl having one >CH--CH< replaced by >C═C<, alkyl having one methylene group or two non-adjacent methylene groups replaced by at least one of --O--, --COO-- or --OOC--, alkyl having one methylene group replaced by --CHX--, alkyl with one methylene group or two non-adjacent methylene groups being replaced by at least one of --O--, --COO-- or --OOC--, and one methylene group being replaced by --CHX--, alkyl having >CH--CH replaced by >C═C< with one methylene group or two non-adjacent methylene groups being replaced by at least one of --O--, --COO-- or --OOC--, alkyl having one >CH--CH< replaced by >C═C< with one methylene group replaced by --CHX--, and alkyl having one >CH--CH< replaced by >C═C< with one methylene or two non-adjacent methylene groups being replaced by at least one of --O--, --COO-- or --OOC--, and one methylene group being replaced by --CHX--; and X represents halogen, cyano or methyl; and   c) means for applying an electrical potential to said plate means.   
     
     
       17. A compound of claim 1 of the formula: ##STR14## wherein R 3  and R 4  have a maximum of 18 carbon atoms and each independently represent halogen, cyano, --NCS, --CF 3 , --OCF 3 , alkyl, alkyl having one >CH--CH< replaced by >C═C<, alkyl having one methylene group or two non-adjacent methylene groups replaced by at least one of --O--, --COO-- or --OOC, alkyl having one methylene group replaced by --CHX--, alkyl with one methylene group or two non-adjacent methylene groups being replaced by at least one of --O--, --COO-- or --OOC, and one methylene group being replaced by --CHX--, alkyl having >CH--< replaced by >C═< with one methylene group or two non-adjacent methylene groups being replaced by at least one of --O--, --COO-- or --OOC, alkyl, having one >CH--CH< replaced by >C═C< with one methylene group replaced by --CHX--, and alkyl having one >CH--CH< replaced by >C═C-- with one methylene or two non-adjacent methylene groups being replaced by at least one of --O--, --COO-- or --OOC, and one methylene group being replaced by --CHX--; and X represents halogen, cyano or methyl; X 1  and X 2  each independently denote hydrogen, halogen, cyano or methyl; and ring A 5  represents pyridine-2,5-diyl, pyrimidine-2,5-diyl, and pyrazine-2,5-diyl. 
     
     
       18. A compound of claim 18 of the formula ##STR15##